Electrical characterization of ultra thin HfO2/Al2O3/HfO2 triple-layer gate dielectrics for advanced MIS capacitors

Ultra thin HfO
₂
/Al
₂
O
₃
/HfO
₂
triple-layer gate dielectrics for advanced MIS capacitors have been characterized electrically. The triple-layer gate stacks after post-metal annealing (PMA) at various temperatures have been studied. Experimental results including leakage current, C-V characteristics, and TDDB are presented in this paper. It has been found that the addition of Al
₂
O
₃
into HfO
₂
increases the crystallization temperature of the gate dielectric, and thus reduces the leakage current. The best overall characteristics were obtained by applying PMA at 600 °C.